Nozzle blade assembly comprising replaceable and adjustable nozzle blades



Aug. 2, 1966 A. F. HANSCHKE ETAL 3,263,963

NOZZLE BLADE ASSEMBLY COMPRISING REPLACEABLE AND ADJUSTABLE NOZZLE BLADES 2 Sheets-Sheet 1 Filed Nov. 5, 1964 EG W N W NO R 3 FW TM RA l ll. mm W FIG.2

Aug. 2, 1966 A. F. HANSCHKE ETAL NOZZLE BLADE ASSEMBLY COMPRISING REPLACEABLE AND ADJUSTABLE NOZZLE BLADES 2 Sheets-Sheet 2 Filed Nov. 5, 1964 vvvw FIG.4

.5 ALBERT F. HANSCHKE WILLIAM W. BROWNING FIG United States Patent 3,263,963 NOZZLE BLADE ASSEMBLY COMPRISING RE- PLACEABLE AND ADJUSTABLE NOZZLE BLADES Albert F. Hanschlre and William W. Browning, Wellsville, N.Y., assignors to Worthington Corporation, Harrison, N.J., a corporation of Delaware Filed Nov. 5, 1964, Ser. No. 409,229 8 Claims. (Cl. 25378) This invention relates to nozzle blade assemblies for use in turbines.

An object of the invention is to provide a nozzle blade assembly wherein one or more of the nozzle blades utilized therein may be conveniently replaced without requiring extensive disassembly of the nozzle blade assembly, or the turbine in which the latter is utilized.

Another object of the invention is the provision of a nozzle blade assembly wherein the angular positions of the nozzle blades utilized therein may be conveniently adjusted prior or after final turbine assembly, to provide for optimum turbine performance characteristics without requiring, in either event, extensive disassembly of the nozzle blade assembly, or the turbine in which the latter is utilized.

Another object of the invention is the provision of a nozzle blade assembly which includes conveniently removable means for blocking off a predetermined portion of the turbine inlet area, for turbine test purposes prior to final assembly of the turbine.

A further object of the invention is the provision of a nozzle blade assembly which is particularly, though not exclusively, adaptable for use in radial inlet, double flow power recovery gas turbines.

The above and other objects and advantages of the invention are believed made clear by the following description thereof taken in conjunction with the accompanying detailed drawings wherein:

FIG. 1 is a side view, with parts in section and portions cut away for purposes of illustration, of one of the nozzle blades of the nozzle blade assembly of the invention depicted in operative relationship with portions of the inner case and rotor srtucture of a double flow power recovery gas turbine of the nature referred to hereinabove,

FIG. 2 is a vertical sectional view taken along line 22 of FIG. 1;

FIG. 3 is a vertical sectional view taken through a plurality of the said nozzle blades in the manner indicated by line 3-3 of FIG. 1;

FIG. 4 is a view similar to FIG. 1 and includes the showing of nozzle blank means to block off a predetermined portion of the turbine inlet area; and

FIG. 5 is a vertical sectional view taken along line 5-5 of FIG. 4.

Referring now to FIGS. 1-3 of the drawings, a portion of the annular inner case of a double flow, power recovery gas turbine of the nature referred to hereinabove, is indicated at 10. The inner case includes annular grooves 12 of the depicted shapes formed in opposed interior surfaces thereof. An annular inner case liner 14 of any suitably temperature resistant, thin sheet metal is positioned as shown within the said inner case with freedom for relative expansion therebetween in the manner described in detail in the copending application for US. patent referred to hereinabove.

Generally U-shaped guide and seal members 16 are attached as shown in any convenient manner, as for example spot welding, to the exterior surfaces of the inner case liner 14, and project therefrom into the grooves 12 in the inner case 10.

During operation of the said power recovery turbine,

hot pressurized gases, as for example those exhausted from one or more aircraft-type gas turbines, flow from the interior of the inner case liner 14 into the nozzle blade assembly of the invention in the general direction indicated by the arrows in FIGS. 1 and 3. Although means are preferably provided to generally equalize the temperature and pressure between the interior of the inner case liner 14, and the annular space between the exterior of the said inner case liner and the interior of the inner case 10, as for example a plurality of spaced holes (not shown) extending through the said inner case liner, the latter will expand to a greater degree than the inner case 10 due to the significant difference in the respective thickness thereof. Thus, as a result of such expansion, guide and seal members 16 will abut the interior surfaces of the inner case grooves 12 to limit the movement of the extremities of the inner case liner 14 toward the inner case 10 and maintain the former properly positioned relative to the latter. Further, since the pressurized, high temperature gases have access to the annular space between the inner case 10 and the inner case liner 14 as discussed above, the U-shape of the guide and seal members 16 will substantially prevent theundesirable flow of the hot pressurized gases from the said annular space into the nozzle blades.

Annular grooves 18 are also provided as shown in the respective extremities of the inner case 10, and annular seal members 20 of generally conventional honeycomb construction are positioned in the annular grooves 18 in any convenient manner. The rotor blades of the respective first rotor stages of the double flow, power recovery gas turbine are indicated at 22 and include rotor shrouds 24 of generally conventional construction positioned on the respective tip portions thereof. Projections 26 are formed on the exterior surfaces of the rotor shrouds 24 and cooperate with the seals 20 during rotation of the former to prevent undesirable gas flow around the rotor blades 22. In operation, the hot pressurized gases are divided and flow from the nozzle blade assembly of the invention to the rotor blades 22 in the directions indicated by the curved arrows in the upper portion of FIG. 1.

Horizontally aligned, stepped bores 28 and 30, respectively, are provided as shown in FIG. 1 in the inner case 10 adjacent the respective extremities thereof, and a support bolt 32 extends between the said inner case extremities and through the said stepped bores. The support bolt 32 includes enlarged, generally circular head portions 34 and 35, respectively, fonned thereon adjacent the extremities of the said support bolt. The said enlarged head portions cooperate as shown with adjacent wall portions of the stepped bores 28 and 30 to assist in fixing the position of the support bolt 32 relative to the inner case 10. Screw threads 36 are formed on one extremity of the support bolt 32 as seen in FIG. 1, and locking nuts 38 are threadably attached thereto with the innermost of the said locking nuts cooperating with the adjacent wall portion of stepped bore 30 to secure the support bolt 32 in the depicted position thereof relative to the inner case 10. The support bolt 32 functions to support the nozzle blades of the invention in the manner described in detail hereinbelow. The said support bolt also functions to assist in holding the respective extremities of the inner case 10 in the positions thereof depicted in FIG. 1 against the forces exerted thereon by the hot, pressurized gases. The intermediate portion of the support bolt, i.e. that which extends bet-ween the opposed interior surfaces of the inner case 10, is preferbly of any conveniently formed, non-circular shape, as for example that depicted in crosssection in FIG. 3, for nozzle blade holding purposes as described in detail hereinbelow.

The nozzle blades of the invention are of substantially identical construction, and are indicated generally at 40 in the drawings. Each of the said nozzle blades is of two piece construction comprising a blade profile number 42 of suitable fluid-dynamic configuration, and a correspondingly shaped blade cover plate member 44. The said blade profile and cover plate members are of any suitable, high-temperature resistant material, as for example 410 stainless steel. This is of particular importance because the nozzle blades 40 are subjected to the maximum temperatures of the hot, pressurized gases which may, in many applications, reach 1250 F.

A relatively large mounting groove 46 is formed in each of the blade profile members 42 and is shaped as shown in FIG. 3 in a manner complementary to the non-circular shape of a substantial part of the intermediate portion of the support bolt 32. A mounting groove 48 is similarly formed in each of the cover plate members 44 and is shaped as shown in a manner complementary to the remaining part of the intermediate portion of the support bolt 32, i.e. that which is not covered by the blade profile member 42.

Hollow interior portions 49 and 51, respectively, are formed in the blade profile members 42 and function to permit rapid heating of the nozzle blades 40 without the development of undesirably high thermal stresses therein. In use, the said nozzle blades may be required to withstand heating from ambient atmospheric temperatures to full operating temperature, as for example 1250 F. in only six minutes.

Any suitable attachment means may be utilized to fixedly secure the respective blade profile members 42 and cover plate members 44 to the intermediate portion of the support bolt 32. The said attachment means may, for example, take the form depicted in FIG. 3 wherein attachment screws 50 project as shown through aligned bores in the said blade profile and cover members, respectively, and cooperate with strip nuts 52 positioned within the hollow, interior portions 49 and 51 of the blade profile members 42 to fixedly secure the said blade members to the support bolt upon the tightening of the attachment screws 50. After the said attachment screws .are tightened, the heads thereof are preferably welded over and the exposed surfaces of the resultant welds then ground smooth to present a clean aerodynamic surface to the fiow of the hot gases over the nozzle blades 40. A plurality, as for example twelve, of horizontally spaced, generally aligned pairs of the attachment screws 50 are provided, in the manner illustrated by FIG. 1, to secure each of the nozzle blades 40 to a support bolt 32 in the above-described manner.

Annular heat shields 54 and 56 are positioned as shown in any convenient manner on the surfaces of the inner case which are adjacent the respective extremities of the nozzle blades 40, and are thus subjected to the full temperature of the hot gases flowing over the said nozzle blades. The said heat shields may be of any suitable, high-temperature resistant material, and function to prevent undesirable, localized heat scarring of the said inner case surfaces by the hot gases. Suitable apertures are of course provided in the heat shields 54 and 56 to enable the passage of the support bolt 32 therethrough. Slight clearance is provided between the extremities of the nozzle blades 40 and the said heat shields to provide for expansion of the nozzle blades relative to the inner case 10. The extent of such expansion is, however, kept to a minimum by the provision of means, as discussed above, whereby the inner case 10 is subjected to the hot gases at temperatures only slightly below the maximum thereof.

A plurality of spaced bores 62 are formed in the enlarged, generally circular head portion 34 of the support bolt 32 and a tapped bore 64 is formed in the adjacent wall of the stepped bore 28 in inner case 10. A set screw 66, including an enlarged head portion 68, is provided and extends as shown through one of the bores 54 in the enlarged head portion 34 into the tapped bore 64 to positively prevent rotation of the said support bolt within the said inner case. T-hus, rotation of the nozzle blades 40 relative to the said inner case is similarly prevented. A plurality of the said spaced bores 62 are provided to make possible the positive positioning of the nozzle blades 40 relative to the inner case 10 in any of a plurality of angular positions relative thereto. Thus may be readily understood whereby the angular positions of the nozzle blades 40 may be conveniently varied in accordance with variation in the energy characteristics of the hot pressurized gases and/or the operational requirements of the power recovery turbine, as is well known, to insure maximum operational efficiency of the latter under a variety of operational conditions.

The outer extremity of stepped bore 28 in inner case 10 is screw threaded to receive a correspondingly screw threaded lock nut 70 therein, with the said lock nut functioning to prevent set screw 66 from loosening in tapped bore 64. The said 'lock nut 70 includes a central bore 72 formed therein, and an extension 74 of any conveniently formed non-circular shape, as for example the generally square shape depicted in FIG. 2 is provided on the support bolt 32 and extends as shown through the said central bore 72. The extension 74 functions to facilitate rotational adjustment of the support bolt 32 relative to the inner case 10 upon the removal of the lock nut 70, the set screw 66, and the loosening of locking nuts 38.

In assembling the nozzle blade assembly of the invention, the heat shields 54 and 56 are first spun into the inner case 10 to assume the depicted positions thereof. The support bolt 32 is then inserted through stepped bores 28 and 30 in that order, it being noted that the outer diameter of enlarged head portion 35 of the support bolt 32 is always made less than the smallest inner diameter of the stepped bore 28 to enable the insertion of the support bolt therethrough.

After the said support bolts are inserted in the said stepped bore, the blade profile members 42 and blade cover plate members 44 are positioned on the intermediate portions of the support bolts in the manner made clear by FIG. 3 and the attachment screws 50 then tightened into the strip nuts 52 to fixedly secure the said blade profile and cover members to the said support bolts. The heads of the said attachment screws are then Welded over and the resultant welds ground smooth. The angular positions of the nozzle blades 40 relative to the inner case 10 are then conveniently adjusted through the use of support bolt extension 74 and the loosening and 1etightening of locking nuts 38, after which the locking nuts 38 are tightened to maintain the nozzle blades in the positions thereof to which they have been adjusted during this stage of the assembly process.

Bore 64 is next drilled and tapped in inner case 10 through any desired one of the bores 62 in the enlarged head portion 34 of the support bolt 32. The set screw 66 is then tightened into the said bore 64 and lock nut 70 screwed tightly into the threaded portion of stepped bore 28 to prevent the said set screw from coming out of bore 64. A portion of the inner case 10 adjacent the lock nut 70 is then peened as indicated at 76 in FIG. 1 to secure the said lock nut in place to complete the assembly operation. In practice, the 360 nozzle blade assembly of the invention is preferably constructed in two half-sections of 180 extent, which are attached together to form the 360 assembly in any convenient, readily releasable manner. An outer case of relatively thin, sheet metal is preferably positioned around the assembled nozzle blade assembly and inner case to provide for exhaust gas guidance and a neat, substantially enclosed appearance of the power recovery turbine.

Should the replacement of one or more of the nozzle blades 40 prove necessary or desirable, as for example because of operational damage thereto or generally prolonged usage thereof, all that is required after the said 180 nozzle blade assembly half-sections have been separated, is the dul-ling out of the welds over the attachment screws 50 of the particular blade or blades that warrant replacement, the removal of the said screws, the removal of the blade cover plate member 44 and blade profile member 42 from the intermediate portion of the support bolt 32 in that order, and the attachment of new blade profile and blade cover plate members to the said support bolt portion through the use of new attachment screws as described above. Thus is made clear whereby applicants improved nozzle blade assembly enables the convenient replacement of one or more of the nozzle blades thereof, in situ without requiring extensive disassembly of the said nozzle blade assembly. Replacement of all of the nozzle blades 40, as for example by nozzle blades of improved design and operational characteristics, could of course be effected in the same convenient manner.

Adjustment of the angular positions of the nozzle blades 40 relative to the inner case after final turbine assembly to provide for different operational characteristics of the power recovery turbine as discussed above, would require only sufficient disassembly of the said power recovery turbine to expose the locking nuts 38 and 70, respectively. Ordinarily, this would not require separation of the said 180 nozzle assembly half-sections. With the said locking nuts 38 and 70 exposed, angular adjustment of the nozzle blades 40 would require only the loosening of locking nuts 38, the removal of locking nut 70 and of set screw 66, the adjustment of the angularity of the nozzle blades 40 through the use of support bolt extensions 74 to align a different bore 62 with tapped bore 64, the re-tightening of locking nuts 38, the re-insertion of set screw 66 through the said bore 62 into tapped bore 64, the re-tightening of locking nut 70 to maintain the said set screw in the said tapped bore, and the re-peening of a portion of the inner case 10 adjacent the said locking nut 70. This is made clear whereby the convenient adjustment of the angular positions of the nozzle blades, in situ, is made possible by applicants improved nozzle blade assembly construction.

During initial assembly of the power recovery turbine, the improved construction of the nozzle blade assembly makes possible the testing, under operational conditions, of the power recovery turbine with only locking nuts 38 functioning to maintain the angular positions of the nozzle blades 40. Thus, the power recovery turbine may be operated with the said nozzle blades in a plurality of dilferent angular positions thereof through the simple loosening of the said locking nuts 38, the adjustment of the said nozzle blades to different angular positions there of in the manner described above, and the re-tightening of the said locking nuts to temporarily maintain the nozzle blades in position until it is determined which of the said angular positions provides optimum turbine efficiency under actual operating conditions, whereupon the locking nuts 39 may be finally tightened, the bores 64 drilled and tapped in the inner case 10 through the bores 68, and the assembly of the nozzle blade assembly completed as described above.

FIGURES 4 and 5 depict the nozzle blade assembly of the invention with means included therein for blocking off a predetermined portion of the turbine inlet area, i.e. the area between the opposed extremities of inner case 10, to the flow of the hot, pressurized gases. Such means are particularly useful, for example, in the testing of the power recovery turbine to determine temperature and pressure drops across various stages of the turbine, and make possible the performance of such tests with substantially reduced hot, pressurized gas requirements. Thus, in the rotor testing of a power recovery turbine of the nature referred to hereinabove wherein the hot pressurized gases are normally supplied thereto in operation from the exhausts of two aircraft type gas turbines commonly referred to as jet engines which are directed into the annular inner case 10, the use of the said blocking means makes possible the rotational testing of the rotor prior to final assembly of the turbine through the use of the exhaust from only one such jet engine to thus significantly simplify the test procedures. Whenever the nozzle blocking means are utilized as part of the nozzle blade assembly for turbine test applications, the power recovery turbine no longer operates as a double flow machine, but rather, the hot pressurized gases enter through the reduced turbine inlet area from the inner case 10, flow between the nozzle blades of reduced extent, and flow therefrom in only one general direction through only one side of the turbine rotor as indicated by the curved arrow in FIG. 4.

To this effect, nozzle blades of generally one-half of the longitudinal blade extent of the nozzle blades 40 of FIGS. l-3 are utilized. The said nozzle blades 80 are otherwise of the same construction as the nozzle blades 40 with each of the former comprising a blade profile member 82, a blade cover plate member 84 of correspondingly reduced longitudinal extent, affixed as shown to the support bolt 32 by a plurality of attachment screws 50, and strips nuts 52, respectively, in the manner described in detail hereinabove.

A nozzle blank is generally indicated at 86 and is provided to block off half of the turbine inlet area as discussed above. The said nozzle blank is preferably though not necessarily of 360 extent and comprises side walls 87 and 88, respectively, an end wall 89 which extends as shown into loose surface contact with heat shield 54, and an extended end wall 90 which extends as shown just short of surface contact with a spacer disc 92 provided on the turbine wheel of the power recovery turbine. The respective side and end Walls of the nozzle blank 86 are fixedly secured together in any convenient manner, as for example by welding as indicated at 91, Thus may be readily understood whereby the blocking effect of side wall 87 and end walls 89 and 90 of the nozzle blank 86 enables the flow of the hot, pressurized gases through only one half, or side, of the turbine rotor for the purposes discussed above.

Bores 94 and 96 are provided as shown in the respective end Walls 89 and 90 of the nozzle blank 86 to enable the passage of the support bolt 32 therethrough. A split washer 98 is positioned as shown in bore 96 and functions to prevent the fiow of the hot gases into the interior of the nozzle blank. The split washer 98 also extends into surface contact with the adjacent extremity of the nozzle blade 80 to thus provide a bearing surface for rotational movement of the said nozzle blade upon rotation of support bolt 32 relative to the nozzle blank 86.

The nozzle blank 86 is maintained in the depicted position thereof from the inner case 10 by a plurality of holding straps 100 which are attached as shown to the inner vcase 10 and the nozzle blank 86 by bolts 102 and 104, respectively.

The nozzle blades 80 are adjustable and replaceable in the same manner as are the nozzle blades 40 of FIGS. 1-3. Removal of the nozzle blank 86 and replacement of the nozzle blades 80 with full length nozzle blades 40 requires only the removal of the nozzle blades 80 from the support bolt 32 in the manner described above for the removal of nozzle blades 40 from the said support bolt, the removal of the support bolt from the stepped bores 28 and 30 in the inner case 10, the removal of the holding straps 100 by the loosening of bolts 102 and 104, the removal of the nozzle blank 86 and split Washers 98, the re-insertion of the said support bolt into the said stepped bores, and the attachment of nozzle blades 40 to the former and the proper angular positioning of the said nozzle blades in the manner described above.

While we have illustrated and described preferred forms of our invention, it will be understood that the invention may be embodied otherwise than as specifically disclosed herein, and that certain changes in the form and arrangement of parts and in the specific manner of practicing the invention may be made without departing from the underlying ideas or principles of the invention within the scope of the appended claims.

We claim:

1. In a nozzle blade'asse'mbly for use in turbines, casing means forming a fluid passage, a support element extending across said fluid passage, a plurality of nozzle blade means adapted to be fixedly joined around said support element to form a nOZZle blade removable means for fixedly joining said nozzle blade means around said support element to form a nozzle blade within said fluid passage, whereby said nozzle blade means may be fixedly joined around or removed from said support element in situ Within said fluid passage.

2. In a nozzle blade assembly as in claim 1 wherein said support element is rotatable from without said casing means and said support element and said nozzle blade extend in the same general direction across said fluid passage whereby the angular position of said nozzle blade within said fluid passage may be adjusted from without said casing by rotation of said support element.

3. In a nozzle blade assembly as in claim 2 further comprising releasable holding means adjacent each end of said support element for cooperating with said casing means to fix said support element against rotation in said casing means, said holding means being releasable from without said casing means.

4. In a nozzle blade assembly as in claim 1 wherein said nozzle blade means comprise a blade profile member and a blade cover plate member with grooves formed therein for forming a hollow, interior blade portion when said profile and cover plate members are joined, said blade portion conforming to the shape of the portion of the support element which extends across said fluid passage.

5. In a turbine nozzle blade assembly as in claim 4 wherein the shape of said support element portion is of non-circular cross section.

6. In a nozzle blade assembly as in claim 3 wherein one of said holding means comprises an enlarged head portion formed adjacent one end of said support element, a plurality of alignable bores formed in said enlarged head portion and in an adjacent surface of said casing means, and means for extending between said bores t0 fix said support element against rotation relative to said casing.

7. In a nozzle blade assembly for use in turbines, casing means forming a fluid passage, support means extending across said fluid passage, a plurality of nozzle blade means adapted to be joined to form a nozzle blade which extends partially across said fluid passage from one wall of said casing means to an intermediate point in said fluid passage, removable means for joining said nozzle blade means and simultaneously attaching said nozzle blade means to said support means to form a nozzle blade Within said fluid passage which extends partially across said fluid passage from one wall of said casing means to an intermediate point in said fluid passage, means extending along said support means from said intermediate point in said fluid passage to an opposite wall of said casing means for blocking off a predetermined portion of said fluid passage, and means to position said blocking means within said fluid passage concurrently with the support of said nozzle blade therein by said support means.

8. In a nozzle blade assembly as in claim 7 wherein said blocking means comprise a nozzle blank with an aperture formed therein for the passage of said support means therethrough, and said positioning means comprise a holding strap extending between said casing means and said nozzle blank.

References Cited by the Examiner UNITED STATES PATENTS 1,248,168 11/1917 Schmidt 253l22 1,656,006 l/l928 Lieber 253-121 X 2,945,960 7/1960 Obrist 253141 X FOREIGN PATENTS 894,567 3/1944 France. 148,611 2/1904 Germany.

MARTIN P. SCHWADRON, Primary Examiner.

SAMUEL LEVINE, Examiner.

E. A. POWELL, Assistant Examiner. 

1. IN A NOZZLE BLADE ASSEMBLY FOR USE IN TURBINES, CASING MEANS FORMING A FLUID PASSAGE, A SUPPORT ELEMENT EXTENDING ACROSS SAID FLUID PASSAGE, A PLURALITY OF NOZZLE BLADE MEANS ADAPTED TO BE FIXEDLY JOINED AROUND SAID SUPPORT ELEMENT TO FORM A NOZZLE BLADE REMOVABLE MEANS FOR FIXEDLY JOINING SAID NOZZLE BLADE MEANS AROUND SAID SUPPORT ELEMENT OT FORM A NOZZLE BLADE WITHIN SAID FLUID PASSAGE, WHEREBY SAID NOZZLE BLADE MEANS MAY BE FIXEDLY JOINED AROUND OR REMOVED FROM SAID SUPPORT ELEMENT IN SITU WITHIN SAID FLUID PASSAGE. 